This chapter focuses on how children’s everyday knowledge when entering school is different from subject matter knowledge and argues that children’s emotional imagination and motive orientation is a foundation for their acquisition of subject matter knowledge. We discuss how imagination supports children’s generalizations of experience, so that it becomes possible for them to move between the general and the concrete in analyzing and using knowledge about the world. We also argue for a dialectical relationship between the culturally developed content the children’s encounters in their interactions in the world and the formation of mind. Within the cultural-historical approach to learning and development Davydov was the first to clarify how concepts, within a subject matter system, that are related through the historical development of its content may become the foundation for children learning in school. Supporting the development of theoretical thinking among school pupils serves both to develop thinking with subject matter knowledge, and support children’s person formation.